content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf;
  
  /**
   * Parsers to discard unknown fields during parsing.
   */
  public final class DiscardUnknownFieldsParser {
  
    /**
     * Warps a given {@link Parser} into a new {@link Parser} that discards unknown fields during
     * parsing.
     *
     * <p>Usage example:
     * <pre>{@code
       * private final static Parser<Foo> FOO_PARSER = DiscardUnknownFieldsParser.wrap(Foo.parser());
       * Foo parseFooDiscardUnknown(ByteBuffer input) throws IOException {
       *   return FOO_PARSER.parseFrom(input);
       * }
     * }</pre>
     *
     * <p>Like all other implementations of {@code Parser}, this parser is stateless and thread-safe.
     *
     * @param parser The delegated parser that parses messages.
     * @return a {@link Parser} that will discard unknown fields during parsing.
     */
    public static final <T extends Message> Parser<T> wrap(final Parser<T> parser) {
      return new AbstractParser<T>() {
        @Override
        public T parsePartialFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
            throws InvalidProtocolBufferException {
          try {
            input.discardUnknownFields();
            return parser.parsePartialFrom(input, extensionRegistry);
          } finally {
            input.unsetDiscardUnknownFields();
          }
        }
      };
    }
  
    private DiscardUnknownFieldsParser() {}
  }
  